When the Blues’ game against the Colorado Avalanche on Feb. 8 began, Joel Edmundson was on the bench under the bright lights at Scottrade Center. When it ended, he was on the operating table under anesthesia at Barnes-Jewish Hospital.

Edmundson had blocked a team-high 125 shots going into the night and suffered no serious damage, so the third-year defenseman thought nothing of stepping in front of a one-timer off the stick of former teammate Nail Yakupov in the first period.

“Same thing every time — I’m trying to stop the puck from getting in the net,” Edmundson said. “That’s my job to block shots, so I didn’t think twice about it. I knew it was going to be a hard shot. I saw it was coming, so I turned my head like I usually do, and went down.”

Yakupov’s attempt from the top of the right circle went an estimated 18 feet, traveling about 60 miles per hour, before it was deadened by Edmundson’s right forearm. His...